Hi,
Video shows the problem.
https://www.loom.com/share/3005c9e5a89344a19606bc01b4ed9764
The LAY CSS is overriding NInja Forms and the check isn't showing in the check box, same with radio buttons.
wp-content/themes/lay/frontend/assets/css/frontend.style.css?ver=3.3.2
input {
-webkit-appearance: none;
-moz-appearance: none; }